The Collaborative International Dictionary of English v.0.48:

Free will \Free will\
   1. A will free from improper coercion or restraint.
      [1913 Webster]

            To come thus was I not constrained, but did
            On my free will.                      --Shak.
      [1913 Webster]

   2. The power asserted of moral beings of willing or choosing
      without the restraints of physical or absolute necessity.
      [1913 Webster] free-will

WordNet (r) 3.0 (2006):

free will
    n 1: the power of making free choices unconstrained by external
         agencies [syn: free will, discretion]